The 33-year-old ninth seed reached the quarter-finals for the first time, and at the 10th attempt, on Monday by beating Greek teenager Stefanos Tsitsipas 6-4 7-6(8) 7-6(4).

If Wimbledon had become a ‘house of horrors’ since Isner entered the record books with an unforgettable 11-hour epic against Frenchman Nicolas Mahut in 2010 — the longest match in tennis history — it is proving much more welcoming now.

The victory set up a big-serving last-eight clash with Canada’s 13th seed Milos Raonic, who beat Isner’s compatriot Mackenzie McDonald.

The semis will be on Friday if he wins, when Trump is in town, and Isner was asked whether he would like the tennis fan to come and watch him — a rhetorical question given the president’s schedule.

“Certainly. I’d love to have Trump come watch me. That would be awesome. Maybe I’ll tweet at him if I win on Wednesday. I know a lot of people won’t like that, but I don’t care,” he said.

The second week of the tournament has taken Isner into uncharted territory and a break with some unhappy memories.

“I’ve lost a lot of close ones since that match in 2010, a lot of very, very close ones, a lot of deep five-set matches, third round especially,” he said.

The last nine or 10 years, he said, had been marked by disappointment and leaving “sort of hanging my head a little bit. But not the case this year.”

CLOSE CONTEST

There was little in the first set between Isner and Tsitsipas, bidding to become the first Greek to reach a Grand Slam quarter-final. The 19-year-old double-faulted twice when serving to stay in the first set at 4-5.

Despite that lapse he recovered well and pushed Isner all the way in the second set and had a set point in the tiebreak which the American saved with a powerful first serve.

Isner eventually took the tiebreak 10-8 but in a match dominated by serve he could not shake off his stylish young opponent and saved a break point at 4-4 in the third set.

Another tiebreak was inevitable and again Isner’s greater experience was telling as he sealed victory.